This application claims the priority of commonly owned German patent application Ser. No. 199 30 330.4 filed Jul. 2, 1999. The disclosure of the above-referenced German patent application, as well as that of each U.S. and foreign patent and patent application mentioned in the specification of the present application, is incorporated herein by reference.
The invention relates to improvements in apparatus for and in methods of increasing the permeability of wrapping material for rod-shaped products, especially rod-shaped smokers"" products, and more particularly to improvements in methods of and apparatus for perforating tubular envelopes or wrappers of cigarettes or the like.
It is well known to enhance the permeability of cigarette paper or other wrapping material for rod-shaped tobacco fillers and/or rod-shaped filters for tobacco smoke prior as well as subsequent to the conversion of a running web of wrapping material into a tubular envelope forming part of a continuous tobacco-containing rod; the leader of such rod is thereupon severed at regular intervals to yield a succession of discrete cigarettes, cigars, cigarillos or other rod-shaped smokers"" products. It is equally known to enhance the permeability of selected portions of tubular envelopes forming part of discrete plain or filter cigarettes or analogous rod-shaped smokers"" products while the products rotate about their own axes.
As a rule, a modern apparatus for enhancing the permeability of selected portions of a running web or of selected portions of tubular wrappers of successive rod-shaped smokers"" products (hereinafter called cigarettes for short) comprises at least one source of high-energy radiation (such as a laser beam) and means for directing the beam or beams into one or more selected portions of the path for a running web of wrapping material or of the path for successive plain or filter cigarettes. If the apparatus is designed to perforate the finished (tubular) wrappers of plain or filter cigarettes, the cigarettes are caused to roll about their own longitudinal axes while moving sideways past the perforating station. The purpose of the perforating treatment is to ensure that the permeability of the tubular wrappers rises to a value at which an optimum quantity of atmospheric air is caused to enter the column of tobacco smoke flowing from the lighted end of a cigarette toward the mouth of the smoker. Cool atmospheric air is believed to exert a beneficial influence upon the nicotine and/or condensate contents of tobacco smoke.
U.S. Pat. No. 5,148,818 discloses a perforating apparatus which employs a source of coherent radiation (hereinafter called laser).The means for rolling successive cigarettes about their respective axes during advancement past the perforating station employs two coaxial drum-shaped conveyors and an endless flexible band. The path for the cigarettes is flanked by the band on the one hand, and by the conveyors on the other hand. The speed of the belt departs from the peripheral speeds of the conveyors, and this causes the cigarettes to roll about their respective axes. The laser is installed midway between the two rotary conveyors, and the beam of coherent radiation issuing from the laser is caused to circulate while impinging upon a tubular wrapper at a selected frequency to thus provide the wrapper with an array of perforations.
Published German patent application Serial No. 33 10 930 discloses a perforating apparatus wherein the peripheral surface of a rotary drum-shaped conveyor transports a series of cigarettes sideways past a station where the wrappers of the cigarettes are acted upon by a laser beam. The laser is confined in and is caused to move relative to a complex heart-shaped reflector. Such apparatus are complex, bulky and unreliable.
Another perforating apparatus is disclosed in published German patent application Serial No. 34 31 051 which proposes a different combination of a mobile laser and a directing system for the laser beam. The directing system employs a complex array of mirrors and rotary reflectors which are intended to focus a laser beam upon successive cigarettes while the cigarettes rotate about their respective axes and are simultaneously advanced sideways by a rotary conveyor toward, past and beyond the perforating station.
Published German patent application Serial No. 34 31 067 discloses an apparatus which combines the features of the apparatus disclosed in the aforediscussed published German patent applications Serial Nos. 33 10 930 and 34 31 051.
Published German patent application Serial No. 42 18 266 discloses a perforating apparatus wherein the cigarettes are transported and rolled by a set of drum-shaped conveyors. One of the conveyors carries a polygonal mirror which serves to direct a laser beam into the path for the cigarettes.
A further perforating apparatus is disclosed in published German patent application Serial No. 27 51 522. This publication proposes to roll successive cigarettes between the peripheral surface of a rotary drum-shaped conveyor and the complementary concave surface of a stationary rolling member. A laser beam trails successive cigarettes during sidewise movement of the cigarettes in an arcuate rolling channel between the moving peripheral surface of the drum-shaped conveyor and the stationary surface of the rolling member. The movement of the laser beam is initiated and regulated by a rotary drum-shaped member having a mirrored peripheral surface.
A drawback which is common to all of the above-enumerated perforating (permeability enhancing) apparatus is that the space requirements of such apparatus are excessive, that the apparatus are complex and hence expensive, as well as that their perforating action cannot be regulated and maintained with a desired or required degree of accuracy and facility.
Another drawback of certain conventional perforating apparatus is that, owing to their kinematics, the tubular wrapper of a cigarette can be perforated only during one-half of each revolution of a cigarette about its axis. Therefore, such apparatus are set up to expose the cigarettes to the action of laser beams which penetrate through the entire cigarette so that each beam provides two perforations which are angularly offset by 180 degrees. Such solution is not entirely satisfactory because the energy requirements of the laser are very pronounced and also because the dimensions of at least one of two simultaneously burned perforations in the tubular wrapper of the cigarette are excessive.
An object of the invention is to provide an apparatus which is simple, compact and inexpensive and occupies space that is available but is not utilized in many machines or production lines for the making of rod-shaped articles with gas-permeable tubular envelopes.
Another object of the invention is to provide an apparatus which is constructed and assembled in such a way that the beam or beams of coherent radiation need not penetrate transversely across the entire rod-shaped commodity (such as a plain or filter cigarette) at the perforating station.
A further object of the invention is to provide an apparatus which can form perforations while a rod-shaped article rotates through an angle of 360xc2x0 while advancing past the perforating station.
An additional object of the invention is to provide a novel and improved method of manipulating high-energy beams of radiation in the course of enhancing the penetrability of tubular wrappers for rod-shaped tobacco fillers and/or for rod-shaped filters for tobacco smoke.
Still another object of the invention is to provide a novel laser-conveyor combination which can be put to use in the above outlined apparatus.
A further object of the invention is to provide a novel conveyor which can be utilized with a source of high-energy radiation in the apparatus of the present invention.
Another object of the invention is to provide the above outlined apparatus with novel and improved means for rolling rod-shaped articles preparatory to and during enhancement of permeability of their wrappers, such as wrappers made of cigarette paper, tipping paper or the like.
An additional object of the invention is to provide a cigarette making machine which embodies, or cooperates with, an apparatus exhibiting the above outlined novel characteristics.
Still another object of the invention is to provide an apparatus which occupies space that is normally available in a machine or production line for the making of plain and/or filter cigarettes or analogous rod-shaped commodities of the tobacco processing industry.
A further object of the invention is to provide an apparatus which can dispense with mirrored rotary bodies forming part of numerous presently employed apparatus for enhancing the permeability of tubular wrappers of rod-shaped articles being turned out by the tobacco processing industry.
An additional object of the invention is to provide an apparatus which exhibits the above outlined desirable novel characteristics and which can be designed to subject the wrappers of successive rod-shaped articles of the tobacco processing industry to the action of a single beam of high-energy radiation or to simultaneous action of plural high-energy radiation beams.
Another object of the invention is to provide rod-shaped smokers"" products having tubular wrappers which were perforated in accordance with the above outlined method and/or in the above outlined apparatus.
One feature of the instant invention resides in the provision of an apparatus for increasing or enhancing the permeabilities of tubular envelopes or wrappers forming part of rod-shaped commodities and being adapted to be perforated in response to exposure to high-energy radiation. The improved apparatus comprises means for rolling a series of successive rod-shaped commodities sideways along a predetermined path. The rolling means includes an at least partially hollow conveyor having an external surface bounding a portion of the aforementioned path, and the apparatus further comprises a source of high-energy radiation and means for directing at least some of the radiation issuing from the source through the hollow conveyor and against the envelopes of commodities rolling along the aforementioned portion of the predetermined path.
The source can include at least one pulsating laser, and the commodities can include or constitute rod-shaped smokers"" products (such as plain or filter cigarettes, cigars or cigarillos),
The at least partially hollow conveyor can include a hollow rotary drum which is rotatable about a predetermined (e.g., horizontal) axis, and the aforementioned external surface can constitute a cylindrical surface of the hollow drum. The rolling means of such apparatus can further comprise a rolling member (e.g., a stationary rolling member) having a second surface cooperating with the peripheral surface of the hollow drum to bound a channel which defines a portion of the predetermined path.
At least a portion of the radation directing means is or can be located (installed) in the at least partially hollow conveyor. Such radiation directing means can include at least one mobile mirror, e.g., a pivotable mirror.
The improved apparatus further comprises means for supplying the series of commodities into the predetermined path, preferably in such a way that successive commodities of the series are maintained at predetermined (particularly uniform) distances from each other. The rolling means can include means (such as the means for rotating the drum-shaped conveyor) for moving the external surface at a speed which is required to ensure that any point of the envelope of a commodity rolling along the aforementioned portion of the predetermined path covers a distance greater than the circumferential length of a commodity while the supplying means advances each of the successive commodities through one of the predetermined distances. In such apparatus, the radiation directing means preferably includes at least one radiation reflecting element which is movable from a predetermined starting position while directing high-energy radiation upon the envelope of a commodity rolling in the aforementioned portion of the predetermined path (within a predetermined interval of time) back to the starting position. The speed of moving any point of an envelope of a commodity rolling along the aforementioned portion of the predetermined path is preferably such that the interval during which the aforementioned point covers that part of the aforesaid distance which exceeds the circumferential length of an envelope at least matches the predetermined interval of time to thus permit or enable the radiation reflecting element to reassume its starting position while a commodity is on its way into the aforementioned portion of the predetermined path.
The radiation directing means can comprise a mirror having a radiation reflecting surface, and such radiation directing means can further comprise means for pivoting the mirror about an axis which lies in the radiation reflecting surface of the mirror.
As already mentioned above, the at least partially hollow conveyor can comprise a hollow rotary drum-shaped conveyor which is rotatable about a predetermined (such as horizontal) axis, and the means for directing radiation can comprise a mirror which is pivotable about a second axis which (a) is at least substantially parallel to the predetermined axis, or (b) coincides with the predetermined axis. In the latter instance, the radiation directing means is or can be arranged to direct radiation upon the envelope of a commodity in the aforementioned portion of the predetermined path at a distance from the predetermined axis which is less than the radius of the external surface of the hollow drum-shaped conveyor.
The radiation directing means can comprise at least one light refracting element (e.g., a plano-convex lens). Such radiation directing means can further comprise a pivotable mirror; the at least one light refracting element can be disposed between the radiation source and the pivotable mirror, or between the pivotable mirror and the locus of impigement of high-energy radiation upon the envelope of a commodity in the aforementioned portion of the predetermined path.
As a rule, the radiation directing means of the improved apparatus will comprise at least one of (a) a collector lens, (b) a diffractive optical element, and (c) a combination of a collector lens and a diffractive optical element.
If the at least partially hollow conveyor includes or is constituted by a hollow drum which is rotatable about a predetermined (e.g., horizontal) axis and the aforementioned external surface is a cylindrical external surface of the drum, the source can be located outside of such at least partially hollow conveyor and can be set up to direct at least some of the high-energy radiation into the drum along a second path which is at least substantially parallel to the predetermined axis. The radiation directing means of such apparatus can comprise a pivotable mirror which is arranged to direct radiation upon the envelope of a commodity rolling along the aforementioned portion of the predetermined path, and means for deflecting radiation issuing from the source and for directing deflected radiation upon the pivotable mirror.
The at least partially hollow conveyor is provided with at least one opening which is disposed in the external surface of such conveyor and is partially overlapped by a commodity rolling along the aforementioned portion of the predetermined path. The radiation directing means is arranged to direct radiation upon a commodity in the aforementioned portion of the predetermined path from the interior of the at least partially hollow conveyor and through the at least one opening. The at least one opening can constitute an arcuate slot extending at least substantially circumferentially of the cylindrical surface of the hollow drum-shaped conveyor. The path for successive commodities can include or constitute an arcuate channel having its center of curvature at least close to the axis of the cylindrical external surface of the drum-shaped conveyor. The latter can be provided with a plurality of arcuate openings, and the radiation directing means can include means for splitting a beam of coherent radiation issuing from the source into a plurality of discrete beams and means for directing each discrete beam through a different opening of the conveyor.
Another feature of the invention resides in the provision of a method of perforating tubular envelopes of rod-shaped commodities by exposure to high-energy radiation. The method comprises the steps of rolling successive commodities of a series of such commodities sideways along a predetermined path which partially surrounds a hollow conveyor, establishing a source of high-energy radiation (such as a laser which emits a beam of coherent radiation), and directing from the source at least one beam of high-energy radiation in the hollow conveyor (such as into and/or within the hollow conveyor) and thence against the envelopes of successive commodities of the series rolling sideways along the predetermined path.
The establishing step can include locating the source or sources of high-energy radiation outside of the hollow conveyor.
The commodities can constitute rod-shaped smokers"" products (such as plain or filter cigarettes, cigars or cigarillos) each of which has a rod-like filler (e.g., of natural, reconstituted and/or artificial tobacco and/or filter material for tobacco smoke) confined in the respective envelope (e.g., an envelope consisting of or comprising cigarette paper, tipping paper and/or other wrapping material customarily employed in the tobacco processing industry).
The establishing step of the improved method can comprise providing or employing a laser, and the radiation directing step of such method can comprise splitting the at least one beam into a plurality of (e.g., into two) discrete laser beams and directing the discrete laser beams upon different portions of envelopes of successive commodities of the series while the commodities roll sideways along the predetermined path.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved perforating apparatus itself however, both as to its construction and the modes of assembling, installing and utilizing the same, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawings.